1. Field of Invention
The present invention relates to an electrode structure. More particularly, the present invention relates to an electrode having an aluminum reflective layer.
2. Description of Related Art
In a conventional electrode structure, a reflective layer is usually introduced under an electrode, which enables photon to escape from a LED die through multiple reflections so as to avoid the absorption of the photon by the electrode and the decrease in brightness of the device. As a result, the light emitting efficiency increases. However, for multiple metal layers in the electrode structure may exhibit various adhesive forces and material properties under an external force, the electrode structure may be broken and suffer peeling issue. For example, due to the silver electrode having different material property from that of the sapphire substrate, the vapor deposition of a silver electrode on a sapphire substrate is likely to have electrode peeling issue under the application of the external force, resulting in a low adherence to the sapphire substrate in the electrode structure.